CA1276360C - Polymer solutions - Google Patents
Polymer solutionsInfo
- Publication number
- CA1276360C CA1276360C CA000509815A CA509815A CA1276360C CA 1276360 C CA1276360 C CA 1276360C CA 000509815 A CA000509815 A CA 000509815A CA 509815 A CA509815 A CA 509815A CA 1276360 C CA1276360 C CA 1276360C
- Authority
- CA
- Canada
- Prior art keywords
- delta
- solvent mixture
- solution
- component
- sulphonated
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
- 229920000642 polymer Polymers 0.000 title claims abstract description 25
- 239000011877 solvent mixture Substances 0.000 claims abstract description 53
- 239000012528 membrane Substances 0.000 claims abstract description 42
- QYSXJUFSXHHAJI-YRZJJWOYSA-N vitamin D3 Chemical compound C1(/[C@@H]2CC[C@@H]([C@]2(CCC1)C)[C@H](C)CCCC(C)C)=C\C=C1\C[C@@H](O)CCC1=C QYSXJUFSXHHAJI-YRZJJWOYSA-N 0.000 claims abstract description 29
- 239000002904 solvent Substances 0.000 claims abstract description 24
- 239000007788 liquid Substances 0.000 claims abstract description 9
- 238000004519 manufacturing process Methods 0.000 claims abstract description 6
- 230000008018 melting Effects 0.000 claims abstract description 6
- 238000002844 melting Methods 0.000 claims abstract description 6
- 238000001223 reverse osmosis Methods 0.000 claims abstract description 5
- 239000007787 solid Substances 0.000 claims abstract description 5
- ZHNUHDYFZUAESO-UHFFFAOYSA-N Formamide Chemical compound NC=O ZHNUHDYFZUAESO-UHFFFAOYSA-N 0.000 claims description 32
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 claims description 28
- ZWEHNKRNPOVVGH-UHFFFAOYSA-N 2-Butanone Chemical compound CCC(C)=O ZWEHNKRNPOVVGH-UHFFFAOYSA-N 0.000 claims description 27
- 239000000463 material Substances 0.000 claims description 23
- WEVYAHXRMPXWCK-UHFFFAOYSA-N Acetonitrile Chemical compound CC#N WEVYAHXRMPXWCK-UHFFFAOYSA-N 0.000 claims description 22
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 claims description 21
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 20
- 150000001875 compounds Chemical class 0.000 claims description 19
- RYHBNJHYFVUHQT-UHFFFAOYSA-N 1,4-Dioxane Chemical compound C1COCCO1 RYHBNJHYFVUHQT-UHFFFAOYSA-N 0.000 claims description 13
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 13
- 238000005266 casting Methods 0.000 claims description 11
- 238000005345 coagulation Methods 0.000 claims description 11
- 230000015271 coagulation Effects 0.000 claims description 11
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 claims description 9
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 claims description 9
- 238000000034 method Methods 0.000 claims description 9
- 229910052751 metal Inorganic materials 0.000 claims description 8
- 239000002184 metal Substances 0.000 claims description 8
- 125000000843 phenylene group Chemical group C1(=C(C=CC=C1)*)* 0.000 claims description 8
- WFDIJRYMOXRFFG-UHFFFAOYSA-N Acetic anhydride Chemical compound CC(=O)OC(C)=O WFDIJRYMOXRFFG-UHFFFAOYSA-N 0.000 claims description 6
- YMWUJEATGCHHMB-UHFFFAOYSA-N Dichloromethane Chemical compound ClCCl YMWUJEATGCHHMB-UHFFFAOYSA-N 0.000 claims description 6
- XEKOWRVHYACXOJ-UHFFFAOYSA-N Ethyl acetate Chemical compound CCOC(C)=O XEKOWRVHYACXOJ-UHFFFAOYSA-N 0.000 claims description 6
- 125000004435 hydrogen atom Chemical group [H]* 0.000 claims description 5
- HZAXFHJVJLSVMW-UHFFFAOYSA-N 2-Aminoethan-1-ol Chemical compound NCCO HZAXFHJVJLSVMW-UHFFFAOYSA-N 0.000 claims description 4
- POAOYUHQDCAZBD-UHFFFAOYSA-N 2-butoxyethanol Chemical compound CCCCOCCO POAOYUHQDCAZBD-UHFFFAOYSA-N 0.000 claims description 4
- 101000623895 Bos taurus Mucin-15 Proteins 0.000 claims description 4
- HEDRZPFGACZZDS-UHFFFAOYSA-N Chloroform Chemical compound ClC(Cl)Cl HEDRZPFGACZZDS-UHFFFAOYSA-N 0.000 claims description 4
- YNAVUWVOSKDBBP-UHFFFAOYSA-N Morpholine Chemical compound C1COCCN1 YNAVUWVOSKDBBP-UHFFFAOYSA-N 0.000 claims description 4
- RDOXTESZEPMUJZ-UHFFFAOYSA-N anisole Chemical compound COC1=CC=CC=C1 RDOXTESZEPMUJZ-UHFFFAOYSA-N 0.000 claims description 4
- 125000004429 atom Chemical group 0.000 claims description 4
- VZGDMQKNWNREIO-UHFFFAOYSA-N tetrachloromethane Chemical compound ClC(Cl)(Cl)Cl VZGDMQKNWNREIO-UHFFFAOYSA-N 0.000 claims description 4
- ZNQVEEAIQZEUHB-UHFFFAOYSA-N 2-ethoxyethanol Chemical compound CCOCCO ZNQVEEAIQZEUHB-UHFFFAOYSA-N 0.000 claims description 3
- 229940093475 2-ethoxyethanol Drugs 0.000 claims description 3
- 239000007791 liquid phase Substances 0.000 claims description 3
- ATHHXGZTWNVVOU-UHFFFAOYSA-N monomethyl-formamide Natural products CNC=O ATHHXGZTWNVVOU-UHFFFAOYSA-N 0.000 claims description 3
- OZXIZRZFGJZWBF-UHFFFAOYSA-N 1,3,5-trimethyl-2-(2,4,6-trimethylphenoxy)benzene Chemical compound CC1=CC(C)=CC(C)=C1OC1=C(C)C=C(C)C=C1C OZXIZRZFGJZWBF-UHFFFAOYSA-N 0.000 claims description 2
- KMTRUDSVKNLOMY-UHFFFAOYSA-N Ethylene carbonate Chemical compound O=C1OCCO1 KMTRUDSVKNLOMY-UHFFFAOYSA-N 0.000 claims description 2
- 125000000217 alkyl group Chemical group 0.000 claims description 2
- SHOJXDKTYKFBRD-UHFFFAOYSA-N mesityl oxide Natural products CC(C)=CC(C)=O SHOJXDKTYKFBRD-UHFFFAOYSA-N 0.000 claims description 2
- UZKWTJUDCOPSNM-UHFFFAOYSA-N methoxybenzene Substances CCCCOC=C UZKWTJUDCOPSNM-UHFFFAOYSA-N 0.000 claims description 2
- LYGJENNIWJXYER-UHFFFAOYSA-N nitromethane Chemical compound C[N+]([O-])=O LYGJENNIWJXYER-UHFFFAOYSA-N 0.000 claims description 2
- 238000000108 ultra-filtration Methods 0.000 claims description 2
- 239000003643 water by type Substances 0.000 claims description 2
- LRHPLDYGYMQRHN-UHFFFAOYSA-N N-Butanol Chemical compound CCCCO LRHPLDYGYMQRHN-UHFFFAOYSA-N 0.000 claims 3
- MTHSVFCYNBDYFN-UHFFFAOYSA-N diethylene glycol Chemical compound OCCOCCO MTHSVFCYNBDYFN-UHFFFAOYSA-N 0.000 claims 3
- 239000003295 industrial effluent Substances 0.000 claims 1
- RUOJZAUFBMNUDX-UHFFFAOYSA-N propylene carbonate Chemical compound CC1COC(=O)O1 RUOJZAUFBMNUDX-UHFFFAOYSA-N 0.000 claims 1
- 238000000746 purification Methods 0.000 claims 1
- 239000000243 solution Substances 0.000 description 20
- 239000000203 mixture Substances 0.000 description 19
- 229920002492 poly(sulfone) Polymers 0.000 description 19
- 229920001577 copolymer Polymers 0.000 description 9
- 239000003795 chemical substances by application Substances 0.000 description 7
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 6
- 230000008961 swelling Effects 0.000 description 6
- 230000004931 aggregating effect Effects 0.000 description 5
- 125000001033 ether group Chemical group 0.000 description 5
- 150000002500 ions Chemical class 0.000 description 5
- 238000010438 heat treatment Methods 0.000 description 4
- 229910052739 hydrogen Inorganic materials 0.000 description 4
- 239000001257 hydrogen Substances 0.000 description 4
- 150000003839 salts Chemical class 0.000 description 4
- YLQBMQCUIZJEEH-UHFFFAOYSA-N Furan Chemical compound C=1C=COC=1 YLQBMQCUIZJEEH-UHFFFAOYSA-N 0.000 description 3
- ZMXDDKWLCZADIW-UHFFFAOYSA-N N,N-Dimethylformamide Chemical compound CN(C)C=O ZMXDDKWLCZADIW-UHFFFAOYSA-N 0.000 description 3
- 239000007864 aqueous solution Substances 0.000 description 3
- 238000001704 evaporation Methods 0.000 description 3
- 230000008020 evaporation Effects 0.000 description 3
- 239000011780 sodium chloride Substances 0.000 description 3
- CMXPERZAMAQXSF-UHFFFAOYSA-M sodium;1,4-bis(2-ethylhexoxy)-1,4-dioxobutane-2-sulfonate;1,8-dihydroxyanthracene-9,10-dione Chemical compound [Na+].O=C1C2=CC=CC(O)=C2C(=O)C2=C1C=CC=C2O.CCCCC(CC)COC(=O)CC(S([O-])(=O)=O)C(=O)OCC(CC)CCCC CMXPERZAMAQXSF-UHFFFAOYSA-M 0.000 description 3
- 241000894007 species Species 0.000 description 3
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 2
- 241000950638 Symphysodon discus Species 0.000 description 2
- WYURNTSHIVDZCO-UHFFFAOYSA-N Tetrahydrofuran Chemical compound C1CCOC1 WYURNTSHIVDZCO-UHFFFAOYSA-N 0.000 description 2
- -1 cyclic hydrocarbons Chemical class 0.000 description 2
- 230000001419 dependent effect Effects 0.000 description 2
- 239000012153 distilled water Substances 0.000 description 2
- 230000004907 flux Effects 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- WGCNASOHLSPBMP-UHFFFAOYSA-N hydroxyacetaldehyde Natural products OCC=O WGCNASOHLSPBMP-UHFFFAOYSA-N 0.000 description 2
- 238000007654 immersion Methods 0.000 description 2
- 229910017053 inorganic salt Inorganic materials 0.000 description 2
- 238000005342 ion exchange Methods 0.000 description 2
- FDPIMTJIUBPUKL-UHFFFAOYSA-N pentan-3-one Chemical compound CCC(=O)CC FDPIMTJIUBPUKL-UHFFFAOYSA-N 0.000 description 2
- 239000012071 phase Substances 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- VWDWKYIASSYTQR-UHFFFAOYSA-N sodium nitrate Chemical compound [Na+].[O-][N+]([O-])=O VWDWKYIASSYTQR-UHFFFAOYSA-N 0.000 description 2
- BTANRVKWQNVYAZ-SCSAIBSYSA-N (2R)-butan-2-ol Chemical compound CC[C@@H](C)O BTANRVKWQNVYAZ-SCSAIBSYSA-N 0.000 description 1
- 101150034533 ATIC gene Proteins 0.000 description 1
- 241000331231 Amorphocerini gen. n. 1 DAD-2008 Species 0.000 description 1
- 229910001369 Brass Inorganic materials 0.000 description 1
- 101100457461 Caenorhabditis elegans mnm-2 gene Proteins 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 241001630921 Chlorida Species 0.000 description 1
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- OFOBLEOULBTSOW-UHFFFAOYSA-N Propanedioic acid Natural products OC(=O)CC(O)=O OFOBLEOULBTSOW-UHFFFAOYSA-N 0.000 description 1
- 101150057388 Reln gene Proteins 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 1
- DHXVGJBLRPWPCS-UHFFFAOYSA-N Tetrahydropyran Chemical compound C1CCOCC1 DHXVGJBLRPWPCS-UHFFFAOYSA-N 0.000 description 1
- 229910052784 alkaline earth metal Inorganic materials 0.000 description 1
- 150000001342 alkaline earth metals Chemical class 0.000 description 1
- 150000001408 amides Chemical class 0.000 description 1
- 150000008064 anhydrides Chemical class 0.000 description 1
- 239000007900 aqueous suspension Substances 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 239000010951 brass Substances 0.000 description 1
- 150000001735 carboxylic acids Chemical class 0.000 description 1
- 230000001112 coagulating effect Effects 0.000 description 1
- 238000010924 continuous production Methods 0.000 description 1
- 125000000753 cycloalkyl group Chemical group 0.000 description 1
- 238000010612 desalination reaction Methods 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 238000000909 electrodialysis Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000004744 fabric Substances 0.000 description 1
- JEIPFZHSYJVQDO-UHFFFAOYSA-N ferric oxide Chemical compound O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 239000008187 granular material Substances 0.000 description 1
- 229910002804 graphite Inorganic materials 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 239000003456 ion exchange resin Substances 0.000 description 1
- 229920003303 ion-exchange polymer Polymers 0.000 description 1
- VZCYOOQTPOCHFL-UPHRSURJSA-N maleic acid Chemical compound OC(=O)\C=C/C(O)=O VZCYOOQTPOCHFL-UPHRSURJSA-N 0.000 description 1
- 239000011976 maleic acid Substances 0.000 description 1
- 239000012457 nonaqueous media Substances 0.000 description 1
- 239000012466 permeate Substances 0.000 description 1
- 239000002798 polar solvent Substances 0.000 description 1
- 229920000090 poly(aryl ether) Polymers 0.000 description 1
- 229920006254 polymer film Polymers 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- QQONPFPTGQHPMA-UHFFFAOYSA-N propylene Natural products CC=C QQONPFPTGQHPMA-UHFFFAOYSA-N 0.000 description 1
- 125000004805 propylene group Chemical group [H]C([H])([H])C([H])([*:1])C([H])([H])[*:2] 0.000 description 1
- BALXUFOVQVENIU-KXNXZCPBSA-N pseudoephedrine hydrochloride Chemical compound [H+].[Cl-].CN[C@@H](C)[C@@H](O)C1=CC=CC=C1 BALXUFOVQVENIU-KXNXZCPBSA-N 0.000 description 1
- 230000003014 reinforcing effect Effects 0.000 description 1
- 239000013557 residual solvent Substances 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 239000004317 sodium nitrate Substances 0.000 description 1
- 235000010344 sodium nitrate Nutrition 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000001117 sulphuric acid Substances 0.000 description 1
- 235000011149 sulphuric acid Nutrition 0.000 description 1
- 230000000153 supplemental effect Effects 0.000 description 1
- 238000004448 titration Methods 0.000 description 1
- VZCYOOQTPOCHFL-UHFFFAOYSA-N trans-butenedioic acid Natural products OC(=O)C=CC(O)=O VZCYOOQTPOCHFL-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J3/00—Processes of treating or compounding macromolecular substances
- C08J3/02—Making solutions, dispersions, lattices or gels by other methods than by solution, emulsion or suspension polymerisation techniques
- C08J3/09—Making solutions, dispersions, lattices or gels by other methods than by solution, emulsion or suspension polymerisation techniques in organic liquids
- C08J3/091—Making solutions, dispersions, lattices or gels by other methods than by solution, emulsion or suspension polymerisation techniques in organic liquids characterised by the chemical constitution of the organic liquid
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D67/00—Processes specially adapted for manufacturing semi-permeable membranes for separation processes or apparatus
- B01D67/0002—Organic membrane manufacture
- B01D67/0009—Organic membrane manufacture by phase separation, sol-gel transition, evaporation or solvent quenching
- B01D67/0011—Casting solutions therefor
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D67/00—Processes specially adapted for manufacturing semi-permeable membranes for separation processes or apparatus
- B01D67/0002—Organic membrane manufacture
- B01D67/0009—Organic membrane manufacture by phase separation, sol-gel transition, evaporation or solvent quenching
- B01D67/0013—Casting processes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
- B01D69/02—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor characterised by their properties
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
- B01D71/06—Organic material
- B01D71/66—Polymers having sulfur in the main chain, with or without nitrogen, oxygen or carbon only
- B01D71/68—Polysulfones; Polyethersulfones
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2325/00—Details relating to properties of membranes
- B01D2325/02—Details relating to pores or porosity of the membranes
- B01D2325/022—Asymmetric membranes
- B01D2325/0233—Asymmetric membranes with clearly distinguishable layers
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J2381/00—Characterised by the use of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing sulfur with or without nitrogen, oxygen, or carbon only; Polysulfones; Derivatives of such polymers
- C08J2381/06—Polysulfones; Polyethersulfones
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Dispersion Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Health & Medical Sciences (AREA)
- General Chemical & Material Sciences (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Separation Using Semi-Permeable Membranes (AREA)
- Compositions Of Macromolecular Compounds (AREA)
- Processes Of Treating Macromolecular Substances (AREA)
- Manufacture Of Macromolecular Shaped Articles (AREA)
Abstract
Abstract A polymer solution contains a sulphonated polyarylenthersulphone in a solvent mixture containing at least three components, where the solvent mixture has a delta-H in the range from 3 to 8.5; a delta-P in the range from 4 to 8 and a delta-D
in the range 7.2 to 9.5 and each component of the solvent mixture is a liquid or low melting solid which is a non-solvent or poor solvent for the sulphonated polyarylenthersulphone, and at least one of the components satisfies at least one of the conditions:-a) said component has a delta-D of less than 8 when the value of delta-P is not more than 3; and b) said component has a delta-H of greater than 3 when the value of delta-P is at least 8.5; and c) said component has a delta-H of less than 8 when it contains at least one hydroxylic group; and d) said component is free of hydroxylic groups and has a delta-P
which is greater than 3 and less than 8.5.
The solution can be used for the production of membranes suitable for use in reverse osmosis applications.
in the range 7.2 to 9.5 and each component of the solvent mixture is a liquid or low melting solid which is a non-solvent or poor solvent for the sulphonated polyarylenthersulphone, and at least one of the components satisfies at least one of the conditions:-a) said component has a delta-D of less than 8 when the value of delta-P is not more than 3; and b) said component has a delta-H of greater than 3 when the value of delta-P is at least 8.5; and c) said component has a delta-H of less than 8 when it contains at least one hydroxylic group; and d) said component is free of hydroxylic groups and has a delta-P
which is greater than 3 and less than 8.5.
The solution can be used for the production of membranes suitable for use in reverse osmosis applications.
Description
~79~36C3 - l ~ H 33495 Poly~er Solutions This invention relates to polymer solutloQs and more pareicularly to the use of s~lch solutlons for the preparation of asymmetric semi-permeAble ~embranes of sulphonated polyarylethersulphones.
Membranes which are useful in separation processes such as ultraf$1tration and reverse osmosis may be prepared by casting solutions of polymeric materials. Asymmetric semi-permeable membranes, which can be used for reverse-osmosls, can be prepared by casting a solution of a film-formlng ion-exchange material on a support and then coagulating the film uslng a non-solvent for the ion-e~cchange material. Asymmetric qemi-permeable membrane~ are characterised by having a thin dense layer which functions as the active layer of the membrane and a thicker porous layer which f~mctions as a reinforcing support for the active layer.
British Patent Specification ~o 1258851 discloses sulphonated polyarylethersulphones having a specified structure~ These materials are disclosed as being ion exchange resins and as being sultable for the produotion of membranes for a ~umber of applications including electrodialysis, fuel cell applications, osmosls and reverse osmosis.
European Patent Specificat~on No 8894 discloses alternative sulphonated polyaryle~hersulphones which may be prepared by a simple and readily controlled sulphonation tecbnique and these materials also may be uæed to produce membranes for desalination and other proces~es.
For the prepara~ion of a solution of a sulphonated polyarylether, ~or example a ~ulphon~ted polyarylethersulphone, various know~ solv2nts for the polymer have bsen proposed, especially aprotic polar solvents such as dimethylfor~amdd~ and dime~hylsulphoxide. Whilst such solvents can be used singly, it ls desirable for the casting solution to eontain a ~ixture of llqu~ds andlor swelling agents and to include at least one material which is a non-solvent or the polymer, for example water, such non-solvent facili~ating coagulation of the polymer film and formation of the afore~entioned asymmatric st~ucture.
~.
, ; . -~2~ 6~
Membranes which are useful in separation processes such as ultraf$1tration and reverse osmosis may be prepared by casting solutions of polymeric materials. Asymmetric semi-permeable membranes, which can be used for reverse-osmosls, can be prepared by casting a solution of a film-formlng ion-exchange material on a support and then coagulating the film uslng a non-solvent for the ion-e~cchange material. Asymmetric qemi-permeable membrane~ are characterised by having a thin dense layer which functions as the active layer of the membrane and a thicker porous layer which f~mctions as a reinforcing support for the active layer.
British Patent Specification ~o 1258851 discloses sulphonated polyarylethersulphones having a specified structure~ These materials are disclosed as being ion exchange resins and as being sultable for the produotion of membranes for a ~umber of applications including electrodialysis, fuel cell applications, osmosls and reverse osmosis.
European Patent Specificat~on No 8894 discloses alternative sulphonated polyaryle~hersulphones which may be prepared by a simple and readily controlled sulphonation tecbnique and these materials also may be uæed to produce membranes for desalination and other proces~es.
For the prepara~ion of a solution of a sulphonated polyarylether, ~or example a ~ulphon~ted polyarylethersulphone, various know~ solv2nts for the polymer have bsen proposed, especially aprotic polar solvents such as dimethylfor~amdd~ and dime~hylsulphoxide. Whilst such solvents can be used singly, it ls desirable for the casting solution to eontain a ~ixture of llqu~ds andlor swelling agents and to include at least one material which is a non-solvent or the polymer, for example water, such non-solvent facili~ating coagulation of the polymer film and formation of the afore~entioned asymmatric st~ucture.
~.
, ; . -~2~ 6~
In our non prior published European Patent Applicaclon Publication No 142973, we have di~c:losed ~olutlon~ o~ ~ulphonated polyarylether3ulphones in a solvent con~a~ning specified component~.
By ~he use oE such solutlons, a~ymmetric ~emi-permeable membrane~
can be produced which hava a useful combination of flux and s< re;ection propertie~. We have now found other solvent mixture~ may be used to obtain polymer solution~ which are suitable for the production of asy~metric semi-permeable membranes.
Accordlng to the present invention there is provided a ~olution of a sulpbonated polyarylethersulphone ~n a solvent mixture wherein the solven~ mixture has a delta-H in the range from 3 to 8.5;
a delta-P in the range from 4 to 8 and a delta-D in the range from 7.2 to 9.5 and the solvent mixture contains at least three co~ponents, each of which is a llquid or a low melting solid whlch is a non- solvent or poor solvent for the sulphonated polyaryletheriulphone wherein a~ least one component of the solvent mixture ls a compound which has a delta-H, a delta-P and a delta-D
having values such that at least one of conditions (a), (b), (c) and/or (d) is sa~isfied:-a) delta-D is le~s than 8 whe~ delta-P iB not ~ore than 3;
b) del~a-H is greater than 3 when delta-P i~ at least 805;
c) delta-a is less than 8 when thç compound contain~ at lea~t one hydroxylic group;
d) delta-P is greater than 3 and le68 than 8.5 and the compound is free of hydroxylic groups, and, at least in the presence of the sulp~onated polyarylethersulphone, the solve~t mlxture forms a single liquid phase and none of the components of the ~olvent mixture reacts or comple~e~ wi~h another of the component~ of the solvent mixture or wi~h the 3ulphonated polyaryleehersulphone.
For convenience hereafter, the 3ulphonated polyarylethersulphone will be referred to as the `sulphonated poly~ulphone'. Also for convenience hereafter1 the at lea~t one component of the solvent mixture whereof delta-~, delta-P and delta-D
3S satisfles at lea~t one of condition~ (a), (b), ~c) and/or (d) wlll be .
- . - .
-, ' :
~763~) _ 3 _ ~l 33495 referred to as component I.
It will be appreciated that the ~olvent mixture m~y contain more than one compound which satis~ie~ the requirements noted for component I. However, the solvent mixture may al90 include one or more compounds which do ~ot ~atisfy any of conditions (a) (b) (c) and/or (t) Thus, in addiCion to at least one component I, the solvent mixture may contain at leas~ one component which i9 a compound which II) contains at least one hydroxylic group and has a del~a-H with a value of at least 8; or III) has a delta-D with a value oE at least 8 and a delta-P with a value of not more than 3; or IV) has a delta-P with a value of at least 8.5 and a delta-H
. with a value of not more than 3.
For convenience, these additional components of the solven~
mixture will be referred to as components II, III and IV respectively.
The solvent mixture in accordance ~ith the present invention contains at least one component I and op~ionally one or more of each of co~ponents II, III and/or IY~
The component~ of the solvent mixture are liquids or low melting sollds at ambient temperature. By "low melting solid" is meant a material which i~ solid at anbient temperature and has a melting point of not more than 50C. The compone~ts of the solvent mixture preferably form a single liquid phase in the absence o:E the sulphonated polyar~lethersulphone bu~ so~e solvent mixtures form a single liquld phase only o~ ~he addition of the ~ulphonated polyarylethersulpho~e.
In referring both to the solvent mlxture and the components thereof, reference is made to delta-H, delta-D and del~a P. Delta-Hg del~a-D and delta-P are components of ~he solubility parameter of the solvent mixture , and of each material ~hich ls a component of the solvent mdxture, and are related by the expres~ion (delta-0) 3 ~delta-~) + (delta-D) ~ (delta-P) where delta-0 i~ the solubility parameter and is gi~en by the expre~sion (delta-0) ~ ~ v~
~/J ~ , .
where A ~V is the molar cohe5ive ener~y which approximates to ~2~i36~:) _ 4 _ H 33495 El - RT;
the la~ent heat of vaporlsation;
R i~ the gas constant;
T is the abaolute temperature; and V i3 the molar volunte.
More specifically, delta-H is the hydrogen bonding co~ponent of the solubili~y parsmeter, delta-D is the dispersion component of the solubility paraDteter and delta-P is the polar component of the solubility parameter.
The concept of solubility parameters is discussed in many papers in the scientific literature including, inter alia, a paper by C M Hansen in Ind Eng Chem Prod Res Dev 8 March 1969, pctges 2 to 11~ Other papers in which solubili~y parameters are considered are, inter alia, Che~ical Re~iews, 75 (1975), pages 731 to 753, and ~irk-Othmer Encyclopedia of Chemical Technology' Second Edition, Supplemental Vol~e (1971) pages 889 to 910.
A tabulation of values of delta-~, delta-D and delta-P i~
given ln the ~an~e~ paper and these ntay be used ~o determine suitable materials for use as component I, and optional components II~ III and/or IV of the solvent mi~ture.
Materials or use as component I include materials which satisfy one or more of conditions (a), (b), (c) and/or (d). Ethyl acetate has a delta-D of 7.44, a delta-P of 2.6 snd a delta-H of 4.5 and hettce satisfies condition ~a~. Formamide has a delta-D of 8.4, a delta-P of 12.8 and a delta-~ of 9.30 and hence satisfies condition (b).
Acetic acid ~delta D is 7.1, delta~P is 3.9 and delta-~ is 6.6~, 2-ethoxyethanol (delta-D i9 7.35, delta-P is 4.5 and delta-H is 7.0), and 2-butoxyethanol ~delta-D i~ 7.76, delta-P is 3~1 and delta-H is 5.9) are all compounds con~aining a hydroxylic group and with a delta-H of less than 8 and hence all satisfy condition (c). l-butanol has a delta D of 7.81, a delta-P of 2.8 and a delta-~ of 7.1 and~ since it contalns a hydroxylic group, satisfies cnnditions (a) and (c~. Compounds which do not contain a hydroxyllc group and for which the v~tlue of delta-P i6 greater than 3 and less than 8.5 include 2cetlc anhydride (delta-D is 7.5, delta-P is 5.4 and delta-a is 4.7), (delta-~ ls 7.58, delta-P is 5.1 and delta-H ls 3.4)~ methyl ethyl ketone (delta-~ is 7~77, del~a-P
.
' .
i3~
_ 5 _ H 33495 is 4.4 and delta-H is 2.5) mesityl oxide (delta-D is 7.97, delta-P i~
By ~he use oE such solutlons, a~ymmetric ~emi-permeable membrane~
can be produced which hava a useful combination of flux and s< re;ection propertie~. We have now found other solvent mixture~ may be used to obtain polymer solution~ which are suitable for the production of asy~metric semi-permeable membranes.
Accordlng to the present invention there is provided a ~olution of a sulpbonated polyarylethersulphone ~n a solvent mixture wherein the solven~ mixture has a delta-H in the range from 3 to 8.5;
a delta-P in the range from 4 to 8 and a delta-D in the range from 7.2 to 9.5 and the solvent mixture contains at least three co~ponents, each of which is a llquid or a low melting solid whlch is a non- solvent or poor solvent for the sulphonated polyaryletheriulphone wherein a~ least one component of the solvent mixture ls a compound which has a delta-H, a delta-P and a delta-D
having values such that at least one of conditions (a), (b), (c) and/or (d) is sa~isfied:-a) delta-D is le~s than 8 whe~ delta-P iB not ~ore than 3;
b) del~a-H is greater than 3 when delta-P i~ at least 805;
c) delta-a is less than 8 when thç compound contain~ at lea~t one hydroxylic group;
d) delta-P is greater than 3 and le68 than 8.5 and the compound is free of hydroxylic groups, and, at least in the presence of the sulp~onated polyarylethersulphone, the solve~t mlxture forms a single liquid phase and none of the components of the ~olvent mixture reacts or comple~e~ wi~h another of the component~ of the solvent mixture or wi~h the 3ulphonated polyaryleehersulphone.
For convenience hereafter, the 3ulphonated polyarylethersulphone will be referred to as the `sulphonated poly~ulphone'. Also for convenience hereafter1 the at lea~t one component of the solvent mixture whereof delta-~, delta-P and delta-D
3S satisfles at lea~t one of condition~ (a), (b), ~c) and/or (d) wlll be .
- . - .
-, ' :
~763~) _ 3 _ ~l 33495 referred to as component I.
It will be appreciated that the ~olvent mixture m~y contain more than one compound which satis~ie~ the requirements noted for component I. However, the solvent mixture may al90 include one or more compounds which do ~ot ~atisfy any of conditions (a) (b) (c) and/or (t) Thus, in addiCion to at least one component I, the solvent mixture may contain at leas~ one component which i9 a compound which II) contains at least one hydroxylic group and has a del~a-H with a value of at least 8; or III) has a delta-D with a value oE at least 8 and a delta-P with a value of not more than 3; or IV) has a delta-P with a value of at least 8.5 and a delta-H
. with a value of not more than 3.
For convenience, these additional components of the solven~
mixture will be referred to as components II, III and IV respectively.
The solvent mixture in accordance ~ith the present invention contains at least one component I and op~ionally one or more of each of co~ponents II, III and/or IY~
The component~ of the solvent mixture are liquids or low melting sollds at ambient temperature. By "low melting solid" is meant a material which i~ solid at anbient temperature and has a melting point of not more than 50C. The compone~ts of the solvent mixture preferably form a single liquid phase in the absence o:E the sulphonated polyar~lethersulphone bu~ so~e solvent mixtures form a single liquld phase only o~ ~he addition of the ~ulphonated polyarylethersulpho~e.
In referring both to the solvent mlxture and the components thereof, reference is made to delta-H, delta-D and del~a P. Delta-Hg del~a-D and delta-P are components of ~he solubility parameter of the solvent mixture , and of each material ~hich ls a component of the solvent mdxture, and are related by the expres~ion (delta-0) 3 ~delta-~) + (delta-D) ~ (delta-P) where delta-0 i~ the solubility parameter and is gi~en by the expre~sion (delta-0) ~ ~ v~
~/J ~ , .
where A ~V is the molar cohe5ive ener~y which approximates to ~2~i36~:) _ 4 _ H 33495 El - RT;
the la~ent heat of vaporlsation;
R i~ the gas constant;
T is the abaolute temperature; and V i3 the molar volunte.
More specifically, delta-H is the hydrogen bonding co~ponent of the solubili~y parsmeter, delta-D is the dispersion component of the solubility paraDteter and delta-P is the polar component of the solubility parameter.
The concept of solubility parameters is discussed in many papers in the scientific literature including, inter alia, a paper by C M Hansen in Ind Eng Chem Prod Res Dev 8 March 1969, pctges 2 to 11~ Other papers in which solubili~y parameters are considered are, inter alia, Che~ical Re~iews, 75 (1975), pages 731 to 753, and ~irk-Othmer Encyclopedia of Chemical Technology' Second Edition, Supplemental Vol~e (1971) pages 889 to 910.
A tabulation of values of delta-~, delta-D and delta-P i~
given ln the ~an~e~ paper and these ntay be used ~o determine suitable materials for use as component I, and optional components II~ III and/or IV of the solvent mi~ture.
Materials or use as component I include materials which satisfy one or more of conditions (a), (b), (c) and/or (d). Ethyl acetate has a delta-D of 7.44, a delta-P of 2.6 snd a delta-H of 4.5 and hettce satisfies condition ~a~. Formamide has a delta-D of 8.4, a delta-P of 12.8 and a delta-~ of 9.30 and hence satisfies condition (b).
Acetic acid ~delta D is 7.1, delta~P is 3.9 and delta-~ is 6.6~, 2-ethoxyethanol (delta-D i9 7.35, delta-P is 4.5 and delta-H is 7.0), and 2-butoxyethanol ~delta-D i~ 7.76, delta-P is 3~1 and delta-H is 5.9) are all compounds con~aining a hydroxylic group and with a delta-H of less than 8 and hence all satisfy condition (c). l-butanol has a delta D of 7.81, a delta-P of 2.8 and a delta-~ of 7.1 and~ since it contalns a hydroxylic group, satisfies cnnditions (a) and (c~. Compounds which do not contain a hydroxyllc group and for which the v~tlue of delta-P i6 greater than 3 and less than 8.5 include 2cetlc anhydride (delta-D is 7.5, delta-P is 5.4 and delta-a is 4.7), (delta-~ ls 7.58, delta-P is 5.1 and delta-H ls 3.4)~ methyl ethyl ketone (delta-~ is 7~77, del~a-P
.
' .
i3~
_ 5 _ H 33495 is 4.4 and delta-H is 2.5) mesityl oxide (delta-D is 7.97, delta-P i~
3.5 and delea-H is 3.0), and diethylena trLamine (delta-D i~ 8~IS, delta-P is h.5 and delea-H is 7.0) and hence all ~atl~fy conditlon (d).
~he ~olv~ne mixture may concain only compound~ which are component I and mlxtures of this type include, inter alia, acetone or methylethyl ketone with formamide and diethylene eriamine; acetic acid, acetic anhydride, 2-ethoxye~hanol or 2-butoxyethanol wlth meehyl ethylketone and forma~ide; and 2-ethoxyethanol or 2-butoxyethanol wi~h acetone and formamide.
Preferred materials for use as optional component II of the solvent mixture have a delta-H of at leas~ 8, a delta-D of not more than B and a delta-P of at least 60 Especially preferred materials have a delta-H of greater than 10, a delta-D of less than 8 and a delta-P of at least 6. From the ~ansen paper, few materials have a delta-H of the required value and even less satisfy the requirements for the preferred materials. Materials whlch may be used as optional component II include ethanol, 2-propanol and ethylene glycol and preferred material3 such as dlethylene glycol, water and ethanolamine.
Preferred materials for use as optional component III of the solvent mixture have a delta-D with a value of at least 8, a delta-P
of not more than 3 and a delta-H of not more than 4. Materials satisfylng the requirements include morpholine and preferred materials include, inter alia, 1,4-dioxane, anisole, carbon tetrachloride, chloroform and methylene chloride. Although furan and tetrahydrofuran have the prefer~ed values of delta D, delta-P and delta-H for use as co~ponent III, these ma~erials are excluded due to their tendency to co~ple~ with the æulphonated polysulphone. Many hydrocarbons, particularly cyclic hydrocarbons, have the preferred values of del~a-D, delta-P and del~a-H but do not form a single phase mlxture with many of the other materials used as components I, II and/or IV of the solvent mixture, even in the presence of the sulphonated polysulphone.
Preferred ~aterials for use as optional component IV of the solvent mixture have a delta-P of at least 8.5, a delta-H of not more than 3 and a delta-D of at least 7.5. Materials satisfying the pre~erred requirements include, inter alia, propylene carbonaee, ethylene carbonate, acetonitrile and nitromethane, ~7~ 3~
~ le solvent ml~tur~ contains at least one compound whlch i9 component I and may optionally inlude one or more compou~ld~ which are component II, component III ~nd/or component IV. The components, and the propor~lo~R ~hereof, must be ~uch that the solvent mixture obtained has values of delta-~9 delta-P and dela-D whlch are in the ranges specified. It is preferred that the solvent mixture contains only ~hree component6. Solvent mixtures which contaln at least one component I together with at least one of co~ponent II, component III and component IV include, inter alia, 1,4-dioxane, acetonitrile aud for~amid& (components III, IV and I); 1,4 dioxane, methyl ethyl ketone, and for~amide (components III, I and I); ethylene glycol, ethanol and acetone (components II, II and I) and 2-propanol, acetone and formamide (co~ponents II, I and I).
The sulphonated polysulpho~e which is dissolved in the solvent mixture is preferably one which has repeating units of the formula I.
I ~ Ph - 0 ~ Ph - S02 ~ wherein Ph represents a phenylene residue, preferably a para-phenylene residue, wherein st least some of the groups Ph are sulphonated; and n is 1 or 2 and the value of n can differ along the polymer chain.
Whilst the sulphonated polysulphone may be one in which the value of n is only one or is only ~wo, we prefer to use a copolymer in which the value of n i8 cne for some repeat units and is two for other repeat units, poly~er3 Of ehis type being described, inter alia, in European Patent Speci~icatlon No 8894.
The preferred polymers have repea~ units of the for~ula:-II ~ ph1 0 _ ph2 _ 0 _ phl _ S0 ~
together with the repeat u~its o the formula III ~ Ph - 0 - Ph - S02 T
wherein ~2'7636~
Ph repre0ents a phenylene residue, preferably a para phenylene re~ldue;
Ph represent~ a ph~nylene residue, preferably a para-phenylene residue, having one or two groups -S03M;
M is a hydrogen a~om, a metal atom and/or a group NR , whereln the groups M may be the s~me or different and the proportion of the groups M is sufficient to combine with the un~atisfied valencies of the group -S03; and R is a hydrogen atom or an alkyl group.
The sulphonated polysulphone may also include a proportion of unsulphonated copolymer having repea~ units of the formula IV ~ phl _ 0 _ phl _ o - Ph - S0 ~
together with the repeat units of the formula II and formula IIL, wherein Ph is as defined.
In the repeat units of ~he formula II, when Ph is a~ ortho-or para- phenylene residue, ~here is typically only one group -S0 M
whereas when Ph is a me~a-phenylene residue there are typically t~wo groups -50 M. When Ph is an ortho-phenylene residue, the -S0 M group is located in a position which 1s para- to one ether group and meta-to the other ether group, any further sulphonation occurring to locate the -S0 M in positions meta- to each other.
When ~h is a para-phenylene residue, the -S0 M group is located in a position ortho-to one ether group and meta-to the other e~her group. When Ph i~ a meta-phenylene residue, the -S0 M groups are located in the posi~io~ ortho-to one ether group aQd para-to the other ether group.
The sulphonated copolymers may be prepared by sulphonating a copolymer consiseing of repeat units III and IV. The ~ulphonation is readily effected by dissolving the copolymer in concentrated sulphuric acld (98% w~w) at a~bient temperature and agitating the mixture for a sufficient time for sulphonation of essentially all of the sub-units. - O - Ph - O - in the repeat units of formula IV. The eopol~mer6 which are sub~ected to sulphona~ion suitably have from 1 to 99 mole % of unlts IV and correspondingly from 99 : ' ~ ' , `' "'' '. ' .: . -. . :, ' . ' ' ,: . ........................................... . .
-.' ~ - .
i3~6C~
~ 8 F~ 3~495 to 1 mole X of units III, and especially from 2.5 to 67 mole % of units IV and correapondingly from 97.5 to 33 mole % of units III.
Sulphonation i9 desirably effected to convert ae least 90% of the units IV to the units II. Sulphonation using concentrated sulphuric acid i5 described in ~uropean Patent Specification No 8894.
The sulphonated polysulphones are polymeric materlals of high molecular welght such that ~he reduced viscosity (RV) of the polymer, (measured as a 1% by weight solntion of the polymer in dimethylformamide at 25-C) is at least 0.2 and preferably at least 0.4. The polymer may be such as to give an R~ of up to 2.5, but it is generally preferred that the RV of the polymer does not exceed 2Ø
The copolymer which is to be sulphonated is conveniently prepared using a mixture of ~onomers to produce the desired repeat units III and IV and h~nce the units III and IV are di~tributed in a random fashion along the polymer chain. Hence, in ~he sulphonated copolymer, the units II (and IV) and III are al90 distributed in a random fashion along the polymer chain.
The sulphonated polysulphone contains the groups -S0 M, where M may be hydrogen, a metal atom or a group NR . Sulphonated polysulphone~ in which M is a divalent metal atom, particularly an alkaline earth metal, are the sub~ect of our non prior published European Patent ~pplication Publication No 145305, which also discloses a method for the production of such divalent metal salts and the use thereof for the production of asy~metric semi-pemeable membranes.
As disclosed herein, the components of the solvent ~ixtu~e, and the proportions thereo~, are such that ~he solve~t mixture has a delta-H, ~ delta-P and 8 delta-D having values in speci~ied ranges.
Preferred solvent mixtures are those ln which delta-D has a value of at least 7.5. We have found that the preferred values of delta-~, delta-P a~d delta-D are dependent on the nature of the sulphona~ed poly~ulphone and when a divalent metal ~alt is being used, the preferred value of delta~H is in a more limited xan~e, specifically from 4 to 5~5 Solvent mixtures which may be used in accordance with the present invention include the ~ystems herelnbeore describad.
, ' ' .
36~
_ 9 _ ~l 33~95 The components of the solven~ mi~ture are non~solvents or poor solvents for the sulphonated polysulphone and the polymer ls typically soluble in each of the components in an amount o~ not more than 5% by weight, preferably less than 1% by weight, expecially less than 0.1% by weigh~.
The sulphonated polysulphone is preferably soluble in the solvent mlx~ure in an amnun~ of at least 10% by weight, more preferably at least 15% by weight, especially at lesst 20% by weight, for exæmple 25 to 30~ by weight. The quantity of polymer dissolved in the solvent mixture should be such that the resulting solution can be cast into a membrane and this will be dependent not only on the compone~ts of the solvent mixture but also on the sulphonated polysulphone, the molecular weight of the polymer and the degree of sulphonation of the poly~er.
~s is discu~ed in more detail hereafter, the solutions of the present invention can be used for the production of membranes.
The sol~ent mlxtures consisting of 1,4 - dioxane, acetonitrile and formamide; 1,4-dioxana, methyl ethyl ketone and formamide; and ethylene glycol, ethanol and acetone have been used to produce membranes from sulphonated polysulphones in which M is a hydrogen atom.
It is preferred that at least one component of the æolvent mixture i8 volatile a~d at least partially evaporates under the conditions of casting the solution. Preferably, the remaining components of the sol~ent mlxture are such, and are present in such proportion~, t~at evaporation of some or al:L of the volatile component causes the sulphona~ed polysulphone to become insoluble in the resitu2 of the solvent mixture.
As is discu~sed herein, a wide ra~ge of solveut mixtures can be u~ed. For sulphonated polysulphones containing repeat units of formula II and for~ula IIL, and possibly al~o repeat units o~
formula IV, we have obtained a so~vent ~ixture having satIsfactory characteristics from a mixture consiseing o~ acetonitril~, 1,4-dioxane a~d formamide which contains ~t least 20% b~ w~ight of ac~tonitrile, at least 35% by weight of 1,4-dio~ané and not more than 30% by weight of forma~ide, the tatal a~ounts of three co~ponents aggregating to 100% by weight. We particularly prefer that the mixture contains .
, `
~2"~ 0 20 to 30% by weight of formamide, 20 to 4()~ by weigh~ of acetonitrile and 35 ~o 55% by weight of 1,4-dioxane, the total amounts of the three components aggregatlng to 100~ by weight. Other solvent mixtures con~ist of 1,4-dioxane, methyl ethyl ketone and formamide and contain at least 15~ by weight of 1,4-dioxane, at least 30% by weight of methyl ethyl ketone and not more than 45% by weight of formamide, the total amounts of the three components aggregating to 100Z by weight.
Suitable mixtures contain 20 to 30% by weight of 1,4-dioxane, 40 ~o 50 by weight of methyl ethyl ketone a~d ~5 to 40% by weight of formamide, the total amounts of the three component~ aggregating to 100% by weight.
further solvent mixture consists of ethylene glycol, ethanol and acetone and contains at least 10% by weight of ethylene glycol, at lease 5% by weight of ethanol and not more than 85% by weight of acetone9 the total amounts of the three components aggregating to 100%
by ~eight. Suitable mixtures contain 15 to 25 % by ~eight of ethylene glycol, 5 to 15% by weight of ethanol and 60 to 80 % by weight of acetone, the total amounts of the three compoents aggregating to 100% by weight.
The most suitable mix~ure~ for any particular sulphonated polysulphone depend not only on the basic polymer structure, that is the unsulphonated material, but also upon the sulphonation ratio of the polymer. By sulphonation ratio" we ~ean the ratio of the number of sulphonated phenylene residues in the sulphonated polymer to the nu~ber of unsulphonated phenylene residues in the sulphonated polymer. The sulphonation ratlo ~s pre~erably determlned by C13 .m.r., but inra-red techniques may also be used. ~owever, we have fou~d that titratlon (which gives a measure of the ion-exchange capacity of ~he polymer) generally indicates a lower degree of sulphonation tban is found by n.m.r. or infra-red. Accordingly, although titration can be used, it is not the preferred technique for determining the sulphonation ratio. In general, polymers having lower sulphonation ratios require a solvent mixture in which the value of delta-H and delta-P for the solvent mixture is reduced. The most su~table mixtures for any given sulphonated poly~er can be readily ascertained by trial.
The solution may be prepared by dissolving the sulphonated polysulphone in any ~uitable form, for example powder, chips, granules, .
. 217~3~
a 33495 .
ln the mixed ~olvent to Eorm a ~olutlon which preferably contaLnr~ from 10% to 40% by weight of the s~phonated polysulphone.
Dissolution of the polymer and casting on the the support may be effected at ambient temperature bu~ lower or higher temperatures may be used if de~ired, for example 0C to 100C. However, it will be appreciated that the temperature should be below the boiling point of any of the components of the solvent mixture.
The solution of the sulphonated polysulphone in the solvent mixture may include a swelling agent. A wide range of msterial~ may be used as the swelling agent and these are typically water soluble compounds, especially bifunctiQnal carboxylic acids. Maleic acid is a suitable swelling agent. The amount of the swelllng agent is depende~t on the par~icular swelling agent, the sulphonated polysulphone and ~he solvent mixture but generally will be at least lX by weight of the total composltion (swelling agent, sulphonated poly~ulphone and solvent mixture) and will not usually exceed 10% by we~ght of the total composition~
The solution of the sulphonated polysulphone is formed into a membrane by casting on a ~upportO Casting onto the support may be effected at essentially ambient temperature but lower or higher temperatures may be used if desired. The support may be, for example, a non-porous plane surface such as a glass or metal plate or, alternatively, may be a porou~ support such as a fabric and, where appropriate, i~ may have a shape other than a plane surface.
Sufficient of the solution is ca~t on to the ~upport in conventio~al manner to give a film of the deslred thlckness which may be adjusted as necessary by suitable mechanical means. It is preferred to produce a film havi~g a thickness of at least 20 micrometres and not more than 300 micrometres, most preferably from 50 up to 250 microme~res, and especially from 75 to 200 micrometres. Alternatively, fine hollow fibres may be produced by extruding the sGlution through a die having a central mandrel, allowing some of the solvent to evaporate and then passing the fibres ~hrough a coagulation bath.
It i~ advantageoua to allow at least partial evaporation of at least one component of the solvent mixture from the supported liquid film by exposing the latter to the atmosphere for a short time, .' ~ ' . .
6~) for example 10 seconds ~o 5 minutes~ be~ore i~merslng the ~upported fllm in a coagulation ba~h. l'he coagulation ba~h may contain an aqueo~l~
solution, for exa~ple a ~olution of an inorganic salt such as sodium chloride or sodium nltrate, or May be a non-solvent liquid, or a liquid mixture, for example formed from one or more of the co~ponents of the solvent mi~ture. Preferably, the coagulation bath i8 an aqueou~
solution of a metal salt such as sodium chloride or sodium nitrate.
To obtain a membrane of a higher flux, the coagulation bath may be a mlxture of water and one or more of the components of the solvent mixture used in ca~ting the membrane. The temperature of the coagulation bath is generally between -20C and 60C, and i5 preferably below 5C. The coagula~ion treatment may be between 1 ~inute and and several hours, for example be~ween 5 and 60 minutes.
After the coagulation treatment the membrane is recovered.
In the case of a non-porous support, the membrane is detached from the support but~ in the case of a porous support, the membrane re~ains adhered to the support. The recovered membrane may be sub~ected to heat treatment in order to relax the structure. Such a heat treatment preferably includes an immersion in an aqueous solution o an inorganic salt at an elevated temperature, typically fro~ 70C to 150C. This heat treatment ~ay be effected with the membrane being held under pres~ure (4 to 100 KN/~ ) between porous supports, such as porous graphite, sintered stainle8s steel or filter paper on a non-porous support. Once prspared, and after any heat treatment, the ~embrane i9 preferably washed w~th di8tilled water to remove any residual solvent and/or, free ionic species and i8 then stored in distilled water until required.
Membranes obtained by the method of the invention may be used ~or the treabment of a wide varlety of aqueous ar non-aqueous solutions or suspensions by con~e~tional reverse osmosis or ultrafiltration techniques. In particular they may be used for the purl~ication of water, for exa~ple of brackish waters and i~du trial effluents. The ~embranes may also be used for gas separation.
To reduce the posslbillty of variations i~ membrane properties, it 1~ desirable that all stages in the preparation o~ the cs3~ing solution~ and the casting and coagulation steps, are effected under ':
..
3~C) careEully co-ltrol]ed conditions of tlme, temperature and humldity.
During the casti~g and sub~equent evaporatlon, lt 1~ preferred that the h~idi~y does not exceed about 65% relaeive humldity, ~or example in the range 35 ~o 50% relative humidity.
The accompanying drawing is a diagra~atic representation of a reverse os~o~i~ cell i~ which the membranes of the present inven~ion may be usedO
The cell comprises a closed vessel 1 which i8 divided into two sections internally by a membrane 2. The membrane 2 is in contact with a sheet 3 of a porous material, for example filter paper, and sheet 3 is supported by a porous plate 4 which is not semi-permeable and which assists in preventing mechanical deformation of the membrane 2. The membrane 2, the sheet 3 and porous plate 4 are clamped at their edges to prevent leaking arGund the edges. The vessel 1 is divided by the membrane 2 in~o a large section 5 and a small section 6. The large section 5 is provided with two pipelines 7 and 8 for the supply and removal of liquid. The small section 6 is provided with a pipel~ne 9. In use, liquld under pressure, for ex~mple a dilute (about 0.2% by weight) aqueous solution of sod~um chlorida at a pressure of 4NNm , ~s passed into section 5 of the vessel 1 through pipeline 7 and i9 withdrawn through pipeline 8. The pressure is sufficient to cause rever3e osmosis and some water passes through the membrane 2 into the section 6 ~r~m which it is withdrawn thr~ugh the pipeline 9. The apparatus can be operated at ambient temperature ~about 25C) but higher ~emperatures may be used. In a continuous process, a further pipeline may be connected to ~ection 6 of the vessel 1 whereby a contlnuous flow of a carrier liquid, which is the liquld being collected, is passed through section 6. Other modificatlons and variations may be effected in the mlnner known to those skilled in the art.
Various aspect~ of the present in~ention are illustrated, but not limited, by the following Examples, in whlch all parts and percentages are by weight unles~ otherwise indlcated.
EX~MP~ES 1 TO 3 .
A sulphonated polyarylethersulphone copolymer containi~g about 20 mole % of units II about 80 mole Z of units III (as . . ~ .
~7636~
deflned h~reln) in whlch Phl and ph2 are para-phenylene residues and M i9 a hydrogen a~om, having a sulphonatlon ratio of 1:10, and a reduced vlscosity (as deflned herein) of 0.82 wafi dissolved, at a temperature of 25C, in solvent mixtures to give a 26~ by weight solution of the copolymer in the solvent mi~ture. Detalls of the solvent mi~ures used are given in Table One.
Table One __ -- -....... . . _ _ Example . ~lv~ ~ r~ Delta Component % by Value wei~ht (a) 1. . " 1___,___ _ _ _ ~ .
1 1,4 - dioxane 45 fD 8.44 Acetonitrile 31 ~P 6.3 Formamide 24 ~H 4.6 2 1,4 - d$oxane 24 fiD B.27 Methyl ethyl ke~one 45 ~P 5.8 Formamide 31 ~H 4.5 3 ~thylene glycol 19.4 rD 7.6 Ethanol 9.3 ~P 5.1 _ Acetone 71.3 ~ 5.4 Note to Table O~e (a) Delta values for the solveùt mixture, D is del~a-~ value, P is delta-P value? and H is delta-~ value.
The solution was filtered through a gauze with a mesh size of 30 micrometres and the~ centrifuged at 2000 rpm for 20 to 30 minutes.
The solution was cast on to a gl2ss plate and a fllm of the de~ired thickness was formed on the plate with the ald of a brass ~preader. After a minute evaporation in air, ~oagulation of the film was effected by immersion for 30 minute~ in dlstllled water at about 0C. The glass plate and the membrane formed on it were -63~
removed rom the water and the membrane was removed from the glas~
plate. The membrane was washed with distllled water and then was stored in distilled water until te~ted.
The recovered membrane was tested using an appara~us of the ~ype hereinbefore de3cribed and in which the membrane was placed in contac~ w~ eh a porou3 suppor~ and the exposed side, being the side exposed to the air during casting, was subjected ~o continuous feed of an aqueous solution of sodium chloride (0.2% by weight) p~mped across the ~urface of the membrane at a gauge pressure of 600 p.9.i. (4.14 MNm-2) and a temperature of 25C. The liquid passing through the ~embrane was analysed. The res~lt~ of ehree such experiments are glven in Table Two.
TABLE TWO
. . .
_ . __ _ ~ ~ .
~xampleFilm Thickness(m-dlyxl) S R
(b) ~mm) (c~ (d) _ ___ . _ . . A . _ . ~ _ _ ~_ 1 0.15 Z.15 47.8 2 0.15 1.84 59.4 3 _ _ 0.23 80 0 Notes to Tab~e Two (b) The number~ o~ the Exmples refer to the solvent mixtures as detailed in Table One.
(c) Flu~ is the volum~ (in m ) o~ the solution which passes through the membrane (an area of one m ) in one day and is expressed as m.day (d) S R i~ % salt reJection and i8 determined by mea~urlng the conductivity of the ~olution fed to the membrane cell and measurlng the conductlvity of the ~olution permeating the membrane, aDd i3 given b~ the relatlonshlp ~ salt reJection D 11 - conductivity of permeate x 100 ~ conductivity of feed.
'
~he ~olv~ne mixture may concain only compound~ which are component I and mlxtures of this type include, inter alia, acetone or methylethyl ketone with formamide and diethylene eriamine; acetic acid, acetic anhydride, 2-ethoxye~hanol or 2-butoxyethanol wlth meehyl ethylketone and forma~ide; and 2-ethoxyethanol or 2-butoxyethanol wi~h acetone and formamide.
Preferred materials for use as optional component II of the solvent mixture have a delta-H of at leas~ 8, a delta-D of not more than B and a delta-P of at least 60 Especially preferred materials have a delta-H of greater than 10, a delta-D of less than 8 and a delta-P of at least 6. From the ~ansen paper, few materials have a delta-H of the required value and even less satisfy the requirements for the preferred materials. Materials whlch may be used as optional component II include ethanol, 2-propanol and ethylene glycol and preferred material3 such as dlethylene glycol, water and ethanolamine.
Preferred materials for use as optional component III of the solvent mixture have a delta-D with a value of at least 8, a delta-P
of not more than 3 and a delta-H of not more than 4. Materials satisfylng the requirements include morpholine and preferred materials include, inter alia, 1,4-dioxane, anisole, carbon tetrachloride, chloroform and methylene chloride. Although furan and tetrahydrofuran have the prefer~ed values of delta D, delta-P and delta-H for use as co~ponent III, these ma~erials are excluded due to their tendency to co~ple~ with the æulphonated polysulphone. Many hydrocarbons, particularly cyclic hydrocarbons, have the preferred values of del~a-D, delta-P and del~a-H but do not form a single phase mlxture with many of the other materials used as components I, II and/or IV of the solvent mixture, even in the presence of the sulphonated polysulphone.
Preferred ~aterials for use as optional component IV of the solvent mixture have a delta-P of at least 8.5, a delta-H of not more than 3 and a delta-D of at least 7.5. Materials satisfying the pre~erred requirements include, inter alia, propylene carbonaee, ethylene carbonate, acetonitrile and nitromethane, ~7~ 3~
~ le solvent ml~tur~ contains at least one compound whlch i9 component I and may optionally inlude one or more compou~ld~ which are component II, component III ~nd/or component IV. The components, and the propor~lo~R ~hereof, must be ~uch that the solvent mixture obtained has values of delta-~9 delta-P and dela-D whlch are in the ranges specified. It is preferred that the solvent mixture contains only ~hree component6. Solvent mixtures which contaln at least one component I together with at least one of co~ponent II, component III and component IV include, inter alia, 1,4-dioxane, acetonitrile aud for~amid& (components III, IV and I); 1,4 dioxane, methyl ethyl ketone, and for~amide (components III, I and I); ethylene glycol, ethanol and acetone (components II, II and I) and 2-propanol, acetone and formamide (co~ponents II, I and I).
The sulphonated polysulpho~e which is dissolved in the solvent mixture is preferably one which has repeating units of the formula I.
I ~ Ph - 0 ~ Ph - S02 ~ wherein Ph represents a phenylene residue, preferably a para-phenylene residue, wherein st least some of the groups Ph are sulphonated; and n is 1 or 2 and the value of n can differ along the polymer chain.
Whilst the sulphonated polysulphone may be one in which the value of n is only one or is only ~wo, we prefer to use a copolymer in which the value of n i8 cne for some repeat units and is two for other repeat units, poly~er3 Of ehis type being described, inter alia, in European Patent Speci~icatlon No 8894.
The preferred polymers have repea~ units of the for~ula:-II ~ ph1 0 _ ph2 _ 0 _ phl _ S0 ~
together with the repeat u~its o the formula III ~ Ph - 0 - Ph - S02 T
wherein ~2'7636~
Ph repre0ents a phenylene residue, preferably a para phenylene re~ldue;
Ph represent~ a ph~nylene residue, preferably a para-phenylene residue, having one or two groups -S03M;
M is a hydrogen a~om, a metal atom and/or a group NR , whereln the groups M may be the s~me or different and the proportion of the groups M is sufficient to combine with the un~atisfied valencies of the group -S03; and R is a hydrogen atom or an alkyl group.
The sulphonated polysulphone may also include a proportion of unsulphonated copolymer having repea~ units of the formula IV ~ phl _ 0 _ phl _ o - Ph - S0 ~
together with the repeat units of the formula II and formula IIL, wherein Ph is as defined.
In the repeat units of ~he formula II, when Ph is a~ ortho-or para- phenylene residue, ~here is typically only one group -S0 M
whereas when Ph is a me~a-phenylene residue there are typically t~wo groups -50 M. When Ph is an ortho-phenylene residue, the -S0 M group is located in a position which 1s para- to one ether group and meta-to the other ether group, any further sulphonation occurring to locate the -S0 M in positions meta- to each other.
When ~h is a para-phenylene residue, the -S0 M group is located in a position ortho-to one ether group and meta-to the other e~her group. When Ph i~ a meta-phenylene residue, the -S0 M groups are located in the posi~io~ ortho-to one ether group aQd para-to the other ether group.
The sulphonated copolymers may be prepared by sulphonating a copolymer consiseing of repeat units III and IV. The ~ulphonation is readily effected by dissolving the copolymer in concentrated sulphuric acld (98% w~w) at a~bient temperature and agitating the mixture for a sufficient time for sulphonation of essentially all of the sub-units. - O - Ph - O - in the repeat units of formula IV. The eopol~mer6 which are sub~ected to sulphona~ion suitably have from 1 to 99 mole % of unlts IV and correspondingly from 99 : ' ~ ' , `' "'' '. ' .: . -. . :, ' . ' ' ,: . ........................................... . .
-.' ~ - .
i3~6C~
~ 8 F~ 3~495 to 1 mole X of units III, and especially from 2.5 to 67 mole % of units IV and correapondingly from 97.5 to 33 mole % of units III.
Sulphonation i9 desirably effected to convert ae least 90% of the units IV to the units II. Sulphonation using concentrated sulphuric acid i5 described in ~uropean Patent Specification No 8894.
The sulphonated polysulphones are polymeric materlals of high molecular welght such that ~he reduced viscosity (RV) of the polymer, (measured as a 1% by weight solntion of the polymer in dimethylformamide at 25-C) is at least 0.2 and preferably at least 0.4. The polymer may be such as to give an R~ of up to 2.5, but it is generally preferred that the RV of the polymer does not exceed 2Ø
The copolymer which is to be sulphonated is conveniently prepared using a mixture of ~onomers to produce the desired repeat units III and IV and h~nce the units III and IV are di~tributed in a random fashion along the polymer chain. Hence, in ~he sulphonated copolymer, the units II (and IV) and III are al90 distributed in a random fashion along the polymer chain.
The sulphonated polysulphone contains the groups -S0 M, where M may be hydrogen, a metal atom or a group NR . Sulphonated polysulphone~ in which M is a divalent metal atom, particularly an alkaline earth metal, are the sub~ect of our non prior published European Patent ~pplication Publication No 145305, which also discloses a method for the production of such divalent metal salts and the use thereof for the production of asy~metric semi-pemeable membranes.
As disclosed herein, the components of the solvent ~ixtu~e, and the proportions thereo~, are such that ~he solve~t mixture has a delta-H, ~ delta-P and 8 delta-D having values in speci~ied ranges.
Preferred solvent mixtures are those ln which delta-D has a value of at least 7.5. We have found that the preferred values of delta-~, delta-P a~d delta-D are dependent on the nature of the sulphona~ed poly~ulphone and when a divalent metal ~alt is being used, the preferred value of delta~H is in a more limited xan~e, specifically from 4 to 5~5 Solvent mixtures which may be used in accordance with the present invention include the ~ystems herelnbeore describad.
, ' ' .
36~
_ 9 _ ~l 33~95 The components of the solven~ mi~ture are non~solvents or poor solvents for the sulphonated polysulphone and the polymer ls typically soluble in each of the components in an amount o~ not more than 5% by weight, preferably less than 1% by weight, expecially less than 0.1% by weigh~.
The sulphonated polysulphone is preferably soluble in the solvent mlx~ure in an amnun~ of at least 10% by weight, more preferably at least 15% by weight, especially at lesst 20% by weight, for exæmple 25 to 30~ by weight. The quantity of polymer dissolved in the solvent mixture should be such that the resulting solution can be cast into a membrane and this will be dependent not only on the compone~ts of the solvent mixture but also on the sulphonated polysulphone, the molecular weight of the polymer and the degree of sulphonation of the poly~er.
~s is discu~ed in more detail hereafter, the solutions of the present invention can be used for the production of membranes.
The sol~ent mlxtures consisting of 1,4 - dioxane, acetonitrile and formamide; 1,4-dioxana, methyl ethyl ketone and formamide; and ethylene glycol, ethanol and acetone have been used to produce membranes from sulphonated polysulphones in which M is a hydrogen atom.
It is preferred that at least one component of the æolvent mixture i8 volatile a~d at least partially evaporates under the conditions of casting the solution. Preferably, the remaining components of the sol~ent mlxture are such, and are present in such proportion~, t~at evaporation of some or al:L of the volatile component causes the sulphona~ed polysulphone to become insoluble in the resitu2 of the solvent mixture.
As is discu~sed herein, a wide ra~ge of solveut mixtures can be u~ed. For sulphonated polysulphones containing repeat units of formula II and for~ula IIL, and possibly al~o repeat units o~
formula IV, we have obtained a so~vent ~ixture having satIsfactory characteristics from a mixture consiseing o~ acetonitril~, 1,4-dioxane a~d formamide which contains ~t least 20% b~ w~ight of ac~tonitrile, at least 35% by weight of 1,4-dio~ané and not more than 30% by weight of forma~ide, the tatal a~ounts of three co~ponents aggregating to 100% by weight. We particularly prefer that the mixture contains .
, `
~2"~ 0 20 to 30% by weight of formamide, 20 to 4()~ by weigh~ of acetonitrile and 35 ~o 55% by weight of 1,4-dioxane, the total amounts of the three components aggregatlng to 100~ by weight. Other solvent mixtures con~ist of 1,4-dioxane, methyl ethyl ketone and formamide and contain at least 15~ by weight of 1,4-dioxane, at least 30% by weight of methyl ethyl ketone and not more than 45% by weight of formamide, the total amounts of the three components aggregating to 100Z by weight.
Suitable mixtures contain 20 to 30% by weight of 1,4-dioxane, 40 ~o 50 by weight of methyl ethyl ketone a~d ~5 to 40% by weight of formamide, the total amounts of the three component~ aggregating to 100% by weight.
further solvent mixture consists of ethylene glycol, ethanol and acetone and contains at least 10% by weight of ethylene glycol, at lease 5% by weight of ethanol and not more than 85% by weight of acetone9 the total amounts of the three components aggregating to 100%
by ~eight. Suitable mixtures contain 15 to 25 % by ~eight of ethylene glycol, 5 to 15% by weight of ethanol and 60 to 80 % by weight of acetone, the total amounts of the three compoents aggregating to 100% by weight.
The most suitable mix~ure~ for any particular sulphonated polysulphone depend not only on the basic polymer structure, that is the unsulphonated material, but also upon the sulphonation ratio of the polymer. By sulphonation ratio" we ~ean the ratio of the number of sulphonated phenylene residues in the sulphonated polymer to the nu~ber of unsulphonated phenylene residues in the sulphonated polymer. The sulphonation ratlo ~s pre~erably determlned by C13 .m.r., but inra-red techniques may also be used. ~owever, we have fou~d that titratlon (which gives a measure of the ion-exchange capacity of ~he polymer) generally indicates a lower degree of sulphonation tban is found by n.m.r. or infra-red. Accordingly, although titration can be used, it is not the preferred technique for determining the sulphonation ratio. In general, polymers having lower sulphonation ratios require a solvent mixture in which the value of delta-H and delta-P for the solvent mixture is reduced. The most su~table mixtures for any given sulphonated poly~er can be readily ascertained by trial.
The solution may be prepared by dissolving the sulphonated polysulphone in any ~uitable form, for example powder, chips, granules, .
. 217~3~
a 33495 .
ln the mixed ~olvent to Eorm a ~olutlon which preferably contaLnr~ from 10% to 40% by weight of the s~phonated polysulphone.
Dissolution of the polymer and casting on the the support may be effected at ambient temperature bu~ lower or higher temperatures may be used if de~ired, for example 0C to 100C. However, it will be appreciated that the temperature should be below the boiling point of any of the components of the solvent mixture.
The solution of the sulphonated polysulphone in the solvent mixture may include a swelling agent. A wide range of msterial~ may be used as the swelling agent and these are typically water soluble compounds, especially bifunctiQnal carboxylic acids. Maleic acid is a suitable swelling agent. The amount of the swelllng agent is depende~t on the par~icular swelling agent, the sulphonated polysulphone and ~he solvent mixture but generally will be at least lX by weight of the total composltion (swelling agent, sulphonated poly~ulphone and solvent mixture) and will not usually exceed 10% by we~ght of the total composition~
The solution of the sulphonated polysulphone is formed into a membrane by casting on a ~upportO Casting onto the support may be effected at essentially ambient temperature but lower or higher temperatures may be used if desired. The support may be, for example, a non-porous plane surface such as a glass or metal plate or, alternatively, may be a porou~ support such as a fabric and, where appropriate, i~ may have a shape other than a plane surface.
Sufficient of the solution is ca~t on to the ~upport in conventio~al manner to give a film of the deslred thlckness which may be adjusted as necessary by suitable mechanical means. It is preferred to produce a film havi~g a thickness of at least 20 micrometres and not more than 300 micrometres, most preferably from 50 up to 250 microme~res, and especially from 75 to 200 micrometres. Alternatively, fine hollow fibres may be produced by extruding the sGlution through a die having a central mandrel, allowing some of the solvent to evaporate and then passing the fibres ~hrough a coagulation bath.
It i~ advantageoua to allow at least partial evaporation of at least one component of the solvent mixture from the supported liquid film by exposing the latter to the atmosphere for a short time, .' ~ ' . .
6~) for example 10 seconds ~o 5 minutes~ be~ore i~merslng the ~upported fllm in a coagulation ba~h. l'he coagulation ba~h may contain an aqueo~l~
solution, for exa~ple a ~olution of an inorganic salt such as sodium chloride or sodium nltrate, or May be a non-solvent liquid, or a liquid mixture, for example formed from one or more of the co~ponents of the solvent mi~ture. Preferably, the coagulation bath i8 an aqueou~
solution of a metal salt such as sodium chloride or sodium nitrate.
To obtain a membrane of a higher flux, the coagulation bath may be a mlxture of water and one or more of the components of the solvent mixture used in ca~ting the membrane. The temperature of the coagulation bath is generally between -20C and 60C, and i5 preferably below 5C. The coagula~ion treatment may be between 1 ~inute and and several hours, for example be~ween 5 and 60 minutes.
After the coagulation treatment the membrane is recovered.
In the case of a non-porous support, the membrane is detached from the support but~ in the case of a porous support, the membrane re~ains adhered to the support. The recovered membrane may be sub~ected to heat treatment in order to relax the structure. Such a heat treatment preferably includes an immersion in an aqueous solution o an inorganic salt at an elevated temperature, typically fro~ 70C to 150C. This heat treatment ~ay be effected with the membrane being held under pres~ure (4 to 100 KN/~ ) between porous supports, such as porous graphite, sintered stainle8s steel or filter paper on a non-porous support. Once prspared, and after any heat treatment, the ~embrane i9 preferably washed w~th di8tilled water to remove any residual solvent and/or, free ionic species and i8 then stored in distilled water until required.
Membranes obtained by the method of the invention may be used ~or the treabment of a wide varlety of aqueous ar non-aqueous solutions or suspensions by con~e~tional reverse osmosis or ultrafiltration techniques. In particular they may be used for the purl~ication of water, for exa~ple of brackish waters and i~du trial effluents. The ~embranes may also be used for gas separation.
To reduce the posslbillty of variations i~ membrane properties, it 1~ desirable that all stages in the preparation o~ the cs3~ing solution~ and the casting and coagulation steps, are effected under ':
..
3~C) careEully co-ltrol]ed conditions of tlme, temperature and humldity.
During the casti~g and sub~equent evaporatlon, lt 1~ preferred that the h~idi~y does not exceed about 65% relaeive humldity, ~or example in the range 35 ~o 50% relative humidity.
The accompanying drawing is a diagra~atic representation of a reverse os~o~i~ cell i~ which the membranes of the present inven~ion may be usedO
The cell comprises a closed vessel 1 which i8 divided into two sections internally by a membrane 2. The membrane 2 is in contact with a sheet 3 of a porous material, for example filter paper, and sheet 3 is supported by a porous plate 4 which is not semi-permeable and which assists in preventing mechanical deformation of the membrane 2. The membrane 2, the sheet 3 and porous plate 4 are clamped at their edges to prevent leaking arGund the edges. The vessel 1 is divided by the membrane 2 in~o a large section 5 and a small section 6. The large section 5 is provided with two pipelines 7 and 8 for the supply and removal of liquid. The small section 6 is provided with a pipel~ne 9. In use, liquld under pressure, for ex~mple a dilute (about 0.2% by weight) aqueous solution of sod~um chlorida at a pressure of 4NNm , ~s passed into section 5 of the vessel 1 through pipeline 7 and i9 withdrawn through pipeline 8. The pressure is sufficient to cause rever3e osmosis and some water passes through the membrane 2 into the section 6 ~r~m which it is withdrawn thr~ugh the pipeline 9. The apparatus can be operated at ambient temperature ~about 25C) but higher ~emperatures may be used. In a continuous process, a further pipeline may be connected to ~ection 6 of the vessel 1 whereby a contlnuous flow of a carrier liquid, which is the liquld being collected, is passed through section 6. Other modificatlons and variations may be effected in the mlnner known to those skilled in the art.
Various aspect~ of the present in~ention are illustrated, but not limited, by the following Examples, in whlch all parts and percentages are by weight unles~ otherwise indlcated.
EX~MP~ES 1 TO 3 .
A sulphonated polyarylethersulphone copolymer containi~g about 20 mole % of units II about 80 mole Z of units III (as . . ~ .
~7636~
deflned h~reln) in whlch Phl and ph2 are para-phenylene residues and M i9 a hydrogen a~om, having a sulphonatlon ratio of 1:10, and a reduced vlscosity (as deflned herein) of 0.82 wafi dissolved, at a temperature of 25C, in solvent mixtures to give a 26~ by weight solution of the copolymer in the solvent mi~ture. Detalls of the solvent mi~ures used are given in Table One.
Table One __ -- -....... . . _ _ Example . ~lv~ ~ r~ Delta Component % by Value wei~ht (a) 1. . " 1___,___ _ _ _ ~ .
1 1,4 - dioxane 45 fD 8.44 Acetonitrile 31 ~P 6.3 Formamide 24 ~H 4.6 2 1,4 - d$oxane 24 fiD B.27 Methyl ethyl ke~one 45 ~P 5.8 Formamide 31 ~H 4.5 3 ~thylene glycol 19.4 rD 7.6 Ethanol 9.3 ~P 5.1 _ Acetone 71.3 ~ 5.4 Note to Table O~e (a) Delta values for the solveùt mixture, D is del~a-~ value, P is delta-P value? and H is delta-~ value.
The solution was filtered through a gauze with a mesh size of 30 micrometres and the~ centrifuged at 2000 rpm for 20 to 30 minutes.
The solution was cast on to a gl2ss plate and a fllm of the de~ired thickness was formed on the plate with the ald of a brass ~preader. After a minute evaporation in air, ~oagulation of the film was effected by immersion for 30 minute~ in dlstllled water at about 0C. The glass plate and the membrane formed on it were -63~
removed rom the water and the membrane was removed from the glas~
plate. The membrane was washed with distllled water and then was stored in distilled water until te~ted.
The recovered membrane was tested using an appara~us of the ~ype hereinbefore de3cribed and in which the membrane was placed in contac~ w~ eh a porou3 suppor~ and the exposed side, being the side exposed to the air during casting, was subjected ~o continuous feed of an aqueous solution of sodium chloride (0.2% by weight) p~mped across the ~urface of the membrane at a gauge pressure of 600 p.9.i. (4.14 MNm-2) and a temperature of 25C. The liquid passing through the ~embrane was analysed. The res~lt~ of ehree such experiments are glven in Table Two.
TABLE TWO
. . .
_ . __ _ ~ ~ .
~xampleFilm Thickness(m-dlyxl) S R
(b) ~mm) (c~ (d) _ ___ . _ . . A . _ . ~ _ _ ~_ 1 0.15 Z.15 47.8 2 0.15 1.84 59.4 3 _ _ 0.23 80 0 Notes to Tab~e Two (b) The number~ o~ the Exmples refer to the solvent mixtures as detailed in Table One.
(c) Flu~ is the volum~ (in m ) o~ the solution which passes through the membrane (an area of one m ) in one day and is expressed as m.day (d) S R i~ % salt reJection and i8 determined by mea~urlng the conductivity of the ~olution fed to the membrane cell and measurlng the conductlvity of the ~olution permeating the membrane, aDd i3 given b~ the relatlonshlp ~ salt reJection D 11 - conductivity of permeate x 100 ~ conductivity of feed.
'
Claims (10)
1. A solution of a sulphonated polyarylethersulphone in a solvent mixture wherein the solvent mixture has a delta-H in the range from 3 to 8.5; a delta-P in the range from 4 to 8 and a delta-D
in the range from 7.2 to 9.5 and the solvent mixture contains at least three components, each of which is a liquid or a low melting solid which is a non-solvent or poor solvent for the sulphonated polyarylethersulphone wherein at least one component (I) of the solvent mixture is a compound which has a delta-H, a delta-P and a delta-D having values such that as lest one of conditions (a), (b), (c) and/or (d) is satisfied:-a) delta-D is less than 8 when delta-P is not more than 3, b) delta-H is greater than 3 when delta-P is at least 8.5;
and/or c) delta-H is less than 8 when the compound contains at least one hydroxylic group;
d) delta-P is greater than 3 and less than 8.5 and the compound is free of hydroxylic groups;
and, at least in the presence of the sulphonated polyarylethersulphone, the solvent mixture form a single liquid phase and none of the components of the solvent mixture reacts or complexes with another of the components of the solvent mixture or with the sulphonated polyarylethersulphone.
in the range from 7.2 to 9.5 and the solvent mixture contains at least three components, each of which is a liquid or a low melting solid which is a non-solvent or poor solvent for the sulphonated polyarylethersulphone wherein at least one component (I) of the solvent mixture is a compound which has a delta-H, a delta-P and a delta-D having values such that as lest one of conditions (a), (b), (c) and/or (d) is satisfied:-a) delta-D is less than 8 when delta-P is not more than 3, b) delta-H is greater than 3 when delta-P is at least 8.5;
and/or c) delta-H is less than 8 when the compound contains at least one hydroxylic group;
d) delta-P is greater than 3 and less than 8.5 and the compound is free of hydroxylic groups;
and, at least in the presence of the sulphonated polyarylethersulphone, the solvent mixture form a single liquid phase and none of the components of the solvent mixture reacts or complexes with another of the components of the solvent mixture or with the sulphonated polyarylethersulphone.
2. The solution of claim 1 wherein at least one component of the solvent mixture is a compound which either II) contains at least one hydroxylic group and has a delta-H
with a value of at least 8; or III) has a delta-D with a value of at least 8 and a delta-P with a value of not more than 3; and/or IV) has a delta-P with a value of at least 8.5 and a delta-with a value of not more than 3.
with a value of at least 8; or III) has a delta-D with a value of at least 8 and a delta-P with a value of not more than 3; and/or IV) has a delta-P with a value of at least 8.5 and a delta-with a value of not more than 3.
3. The solution of claim 1 wherein the compound which is component I is selected from ethyl acetate, formamide, acetic acid, 2-ethoxyethanol, 2-butoxyethanol, 1-butanol, acetic anhydride, acetone, methyl ethyl ketone, mesityl oxide and dietbylene triamine.
4. The solution of claim 2 wherein the solvent mixture contains at least one compound which is component II and which is selected from ethanol, 2-propanol, ethylene glycol, diethylene glycol, water and ethanolamine; or at least one compound which is component III and which is selected from morpholine, 1,4-dioxane, anisole, carbon tetrachloride, chloroform and methylene chloride, or at least one compound which it component IV and which it selected from propylene carbonate, ethylene carbonate, acetonitrile and nitromethane.
5. The solution of claim 2 wherein the solvent mixture consists of 1,4-dioxane, acetonitrile and formamide; or 1,4-dioxane, methyl ethyl ketone and formamide; or ethylene glycol, ethanol and acetone.
6. The solution of claim 1 wherein the sulphonated polyarylethersulphone has repeating units of the formula I
I wherein Ph represents a phenylene residue wherein at least some of the groups Ph are sulphonated; and n is 1 or 2 and the value of n can differ along the polymer chain.
I wherein Ph represents a phenylene residue wherein at least some of the groups Ph are sulphonated; and n is 1 or 2 and the value of n can differ along the polymer chain.
7. The solution of claim 6 wherein the sulphonated polyarylethersulphone is a material having repeat units of the formula II ? Ph1 - O - Ph2 - O - Ph1 - SO2 ?
together with repeat units of the formula III ? Ph1 - O - Ph1 - SO2 ?
and optionally units of the formula IV ? Ph1 - O - Ph1 - O -Ph1 - SO2 ?
wherein Ph1 represents a phenylene residue;
Ph2 represents a phenylene residue having one or two groups - SO3M;
M is a hydrogen atom, a metal atom and/or a group NR4, wherein the groups M may be the same or different and the proportion of the groups M is sufficient to combine with the unsatisfied valencies of the group - SO3; and R is a hydrogen atom or an alkyl group;
together with repeat units of the formula III ? Ph1 - O - Ph1 - SO2 ?
and optionally units of the formula IV ? Ph1 - O - Ph1 - O -Ph1 - SO2 ?
wherein Ph1 represents a phenylene residue;
Ph2 represents a phenylene residue having one or two groups - SO3M;
M is a hydrogen atom, a metal atom and/or a group NR4, wherein the groups M may be the same or different and the proportion of the groups M is sufficient to combine with the unsatisfied valencies of the group - SO3; and R is a hydrogen atom or an alkyl group;
8. The solution of claim 1 wherein at least one component of the solvent mixture is volatile and at least partially evaporates when casting a film from the solution.
9. A method for the production of an asymmetric semi-permeable membrane which method comprises forming a solution of a sulphonated polyarylethersulphone in a solvent mixture, as claimed in claim 1, casting the solution on a support to form a film on the support, immersing, in a coagulation bath, the cast film of the solution on the support and recovering a membrane from the coagulation bath.
10. A process for the purification of brackish waters or aqueous industrial effluents by effecting reverse osmosis or ultrafiltration using a membrane obtained by the process of claim 9.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB858513113A GB8513113D0 (en) | 1985-05-23 | 1985-05-23 | Polymer solutions |
GB8513113 | 1985-05-23 |
Publications (1)
Publication Number | Publication Date |
---|---|
CA1276360C true CA1276360C (en) | 1990-11-13 |
Family
ID=10579598
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CA000509815A Expired - Fee Related CA1276360C (en) | 1985-05-23 | 1986-05-23 | Polymer solutions |
Country Status (10)
Country | Link |
---|---|
US (1) | US5112892A (en) |
EP (1) | EP0203755A3 (en) |
JP (1) | JPS6225159A (en) |
AU (1) | AU590882B2 (en) |
CA (1) | CA1276360C (en) |
DK (1) | DK243986A (en) |
ES (1) | ES8707428A1 (en) |
GB (1) | GB8513113D0 (en) |
GR (1) | GR861333B (en) |
ZA (1) | ZA863713B (en) |
Families Citing this family (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB8513114D0 (en) * | 1985-05-23 | 1985-06-26 | Ici Plc | Membranes |
GB8513103D0 (en) * | 1985-05-23 | 1985-06-26 | Ici Plc | Solution of polymeric material |
JP2694341B2 (en) * | 1987-02-04 | 1997-12-24 | ハイドロノーティクス | Improved oxidation resistant film and method of manufacturing the same |
US4990252A (en) * | 1987-02-04 | 1991-02-05 | Hydanautics | Stable membranes from sulfonated polyarylethers |
US5009678A (en) * | 1989-10-31 | 1991-04-23 | Union Carbide Industrial Gases Technology Corporation | Process for recovery of ammonia from an ammonia-containing gas mixture |
DE59309908D1 (en) * | 1992-06-13 | 2000-01-27 | Aventis Res & Tech Gmbh & Co | Polymer electrolyte membrane and process for its manufacture |
US6111051A (en) | 1998-08-07 | 2000-08-29 | Mearthane Products Corporation | Preparation of conductive polyurethanes using a conductive quasi-solution |
DE69933129T2 (en) * | 1998-09-11 | 2007-03-01 | Victrex Mfg. Ltd., Thornton Cleveleys | ION EXCHANGE POLYMERS |
EP1278589A2 (en) * | 2000-05-02 | 2003-01-29 | Bernd Schindler | Sulfonated aryl sulfonate matrices and method of production |
GB0307606D0 (en) * | 2003-04-02 | 2003-05-07 | Victrex Mfg Ltd | Ion-conducting polymeric materials |
KR101491782B1 (en) * | 2012-12-03 | 2015-02-11 | 롯데케미칼 주식회사 | Polymer resin composition for preparing of microfilter membrane or ultrafilter membrane, preparation method of polymer filter membrane, and polymer filter membrane |
FR3030532B1 (en) * | 2014-12-22 | 2018-08-17 | Cdp Innovation | NOVEL POLYMERS CONTAINING AMMONIUM SULPHONATE FUNCTIONS, PROCESSES FOR THEIR PREPARATION AND THEIR USES AS CATALYSTS, ANTIBACTERIALS, FUNGICIDES |
Family Cites Families (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CA1017097A (en) * | 1962-11-06 | 1977-09-06 | Imperial Chemical Industries Limited | Manufacture of polysulphones |
FR2138333B1 (en) * | 1971-05-24 | 1974-03-08 | Rhone Poulenc Sa | |
US3875096A (en) * | 1974-03-20 | 1975-04-01 | Us Interior | Process for the preparation of a stable salt form of a sulfonated polyarylether sulfone |
DE2964904D1 (en) * | 1978-09-05 | 1983-03-31 | Ici Plc | Sulphonated polyarylethersulphone copolymers and process for the manufacture thereof |
EP0041780A1 (en) * | 1980-06-10 | 1981-12-16 | Imperial Chemical Industries Plc | Sulphonated polyaryletherketones |
GB8428525D0 (en) * | 1984-11-12 | 1984-12-19 | Ici Plc | Membranes |
GB8513114D0 (en) * | 1985-05-23 | 1985-06-26 | Ici Plc | Membranes |
-
1985
- 1985-05-23 GB GB858513113A patent/GB8513113D0/en active Pending
-
1986
- 1986-05-13 EP EP86303637A patent/EP0203755A3/en not_active Withdrawn
- 1986-05-19 ZA ZA863713A patent/ZA863713B/en unknown
- 1986-05-22 GR GR861333A patent/GR861333B/en unknown
- 1986-05-22 AU AU57828/86A patent/AU590882B2/en not_active Ceased
- 1986-05-23 JP JP61117704A patent/JPS6225159A/en active Pending
- 1986-05-23 DK DK243986A patent/DK243986A/en not_active Application Discontinuation
- 1986-05-23 ES ES555280A patent/ES8707428A1/en not_active Expired
- 1986-05-23 CA CA000509815A patent/CA1276360C/en not_active Expired - Fee Related
-
1990
- 1990-09-06 US US07/578,294 patent/US5112892A/en not_active Expired - Fee Related
Also Published As
Publication number | Publication date |
---|---|
ES555280A0 (en) | 1987-07-16 |
JPS6225159A (en) | 1987-02-03 |
ZA863713B (en) | 1987-02-25 |
EP0203755A2 (en) | 1986-12-03 |
US5112892A (en) | 1992-05-12 |
DK243986D0 (en) | 1986-05-23 |
DK243986A (en) | 1986-11-24 |
EP0203755A3 (en) | 1988-01-07 |
ES8707428A1 (en) | 1987-07-16 |
GB8513113D0 (en) | 1985-06-26 |
AU590882B2 (en) | 1989-11-23 |
GR861333B (en) | 1986-08-27 |
AU5782886A (en) | 1986-11-27 |
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